Pure electric vehicle uses stored electrical energy to power the electric motor and drive the vehicle, and can also operate accessory drive. Pure electric vehicle may use one or a plurality of stored electrical energy sources. For example, the first source of stored electrical energy, e.g., energy of a battery to provide longer lasting energy while the second source of stored electrical energy, e.g., high-power battery to provide power and energy, e.g., for acceleration of the vehicle.
Hybrid electric vehicle can combine internal combustion engine and motor vehicle powered by the energy storage device (such as traction battery) to drive the vehicle. Such combination can be operated by the internal combustion engine and the electric motor run in their higher efficiency range to improve overall fuel efficiency. For example, the motor may have a higher efficiency when accelerating in standstill status, while the internal combustion engine can have higher efficiency during constant engine operation (such as highway driving). Making the improved initial acceleration of the motor allows the internal combustion engine of the hybrid vehicle smaller and more fuel efficient.
In battery-powered pure electric vehicles and plug-in hybrid electric vehicles, high energy density of the battery if the battery sizes reasonable configuration, then a charge to meet the mileage requirements. However, for high energy density batteries with the same size, they have a relatively lower energy density, and therefore they may not be able to meet the energy demand due to transient acceleration or hill climbing, especially in heavy-duty applications, such as city buses or trucks in particular. In view of this, multiple energy sources or mixing energy sources may be used to meet the demands of vehicle mileage and energy, without unduly increasing the size of a single high energy density battery. Heavy-duty electric vehicles may use high energy density battery and energy battery combinations as mixed energy sources, because such energy batteries with high power density and longer life. However, when introduce multiple energy sources or hybrid energy sources in the vehicle drive system, then the problems of how to achieve efficiently operation of the vehicle driving system by reasonable allocation of multiple energy sources or hybrid energy source and can respond to a variety of working conditions has become problems in this field.
Therefore, it is necessary to provide a system and method to solve at least one of the problems described above.